[Nagiosplug-help] How do i check dhcpd running on remote host

Rajendra Adhikari rajendra at subisu.net.np
Thu Nov 17 02:28:02 CET 2005

The nagios monitor is 3 hops away from the dhcpd server. In between 
there are non-cisco routes and they do not support as dhcp relay agent. 
Nagios monitor do not get IP address from dhcp server.
I have installed the plugin 
#check_dhcp --serverip=
Error: Could not bind socket to interface eth0.  Check your privileges...

It is certain that the dhcp request from nagios monitor will never reach 
the dhcp server as there are routers in between and they do not act as 
dhcp relay agent.
If its not possible in this scenario, then is there any other way to 
check if dhcpd is running on the remote host.


Andreas Ericsson wrote:

> rajendra at subisu.net.np wrote:
>> I have my client (where nagios is installed) on different subnet than 
>> that
>> of the dhcpd server. However, the dhcpd server is reachable. As it is 
>> not
>> on the same boradcast domain there is no way the dhcpd server gets the
>> broadcast request from the client. I guess, it wont work with the 
>> standard
>> plugins.
> No it won't (unless Sean pulled in the dhcp-relay thingie from me). 
> That's why I suggested trying the check_dhcp plugin from the package 
> at http://oss.op5.se/nagios since it's supposed to be able to do this 
> (provided your dhcp-server accepts relayed requests, which I think is 
> impossible to turn off).
>> Is anyone checking the dhcp server running on the separate subnet?
> We have a customer that does. The patch originally came from them. I 
> only modified it to make it accept arguments for the dhcp-server and 
> such.
>> regds,
>> Rajen.
>>> Rajendra Adhikari wrote:
>>>> Can any one suggest how do I check the dhcpd running on the remote 
>>>> host?
>>>> I have tried it with the check_dhcp standard plugins, but could not 
>>>> get
>>>> any responce.  Is it possible from standard check_dhcp, or do I 
>>>> need to
>>>> go for  check by ssh  or some other things. I would be grateful if you
>>>> kindly suggest me the way to do it or  provide some reference  
>>>> about it.
>>> DHCP can only be checked for remote hosts (so far). The DHCP client
>>> sends broadcasts to communicate with the server (it has to, since the
>>> DHCP server will assign the IP), which means you can't check a DHCP
>>> server on a different subnet.
>>> I've tried hacking up a patch for that. You can try using the 
>>> check_dhcp
>>> found in the plugins-package at http://oss.op5.se/nagios
>>> Read the --help output (or possibly the source-code). I don't remember
>>> what options you need to specify off-hand.
>>> Oh, and let me know if it works. :)
>>> -- 
>>> Andreas Ericsson                   andreas.ericsson at op5.se
>>> OP5 AB                             www.op5.se
>>> Tel: +46 8-230225                  Fax: +46 8-230231

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